1. Field of the Invention
The application relates to a method utilized in a wireless communication and a communication device thereof, and more particularly, to a method of handling system information reception in a wireless communication system and a related communication device.
2. Description of the Prior Art
Long Term Evolution wireless communication system (LTE system), an advanced high-speed wireless communication system established upon the 3G mobile telecommunication system, supports only packet-switched transmission, and tends to implement both Medium Access Control (MAC) layer and Radio Link Control (RLC) layer in one single communication site, so that the system structure becomes simple.
In the LTE system, a user equipment (UE) applies a system information acquisition procedure to acquire system information broadcasted by an Evolved Universal Terrestrial Radio Access Network (E-UTRAN) upon selecting and upon re-selecting a cell, after handover completion, after entering the E-UTRAN from another radio access technology (RAT), upon receiving an indication about the presence of an Earthquake and Tsunami Warning System (ETWS) notification, etc. The system information includes most essential and most frequently transmitted parameters that are needed to acquire other information of a cell for connection establishment.
Toward advanced high-speed wireless communication system, such as transmitting data in a higher peak data rate, LTE-Advanced is standardized by the 3rd Generation Partnership Project (3 GPP) as an enhancement of LTE system. LTE-Advanced targets faster switching between power states, improves performance at the cell edge, and includes subjects, such as bandwidth extension, coordinated multipoint transmission/reception (COMP), uplink multiple input multiple output (MIMO), etc.
For bandwidth extension, carrier aggregation is introduced to the LTE-Advanced for extension to wider bandwidth, where two or more component carriers are aggregated, for supporting wider transmission bandwidths (for example up to 100 MHz) and for spectrum aggregation. According to carrier aggregation capability, multiple component carriers are aggregated into overall wider bandwidth, where the UE can establish multiple links corresponding to the multiple component carriers for simultaneously receiving and/or transmitting.
In addition, COMP is considered for LTE-Advanced as a tool to improve coverage of high data rates, cell edge throughput, and system efficiency, which implies dynamic coordination among multiple geographically separated points. That is, when an UE is in a cell-edge region, the UE is able to receive signal from multiple cells, and the multiple cells can receive transmission of the UE.
However, in the LTE system, the system information acquisition is defined for the UE having only one connection to a single cell with a single component carrier. For the UE operated in the LTE-A system, there is no system information acquisition mechanism defined for the UE to acquire system information of additional cells for establishing at least a connection to the additional cells. Therefore, the UE has difficulty in establishing new connections with new cells since the LTE-Advanced system does not specify how the system information acquisition is applied for the UE capable of multiple connections to multiple cells with the same component carrier or different component carriers. Moreover, usage of the system information of the multiple cells is never concerned. Improper usage of the system information of the multiple cells may cause cell configuration problems.